*2018 Journal Impact Factor was established by dividing the number of articles published in 2016 and 2017 with the number of times they are cited in 2018 based on Google Scholar Citation Index database. If 'X' is the total number of articles published in 2016 and 2017, and 'Y' is the number of times these articles were cited in indexed journals during 2018 then, journal impact factor = Y/X